Substrate strips, or called array packaging substrates and mother substrates, are widely implemented in semiconductor packaging processes as basic packaging components, essentially consisting of a plurality of substrate units from tens to hundreds arranged in multiple arrays. After semiconductor packaging, the arrayed substrates are singulated into individual packages each having one substrate unit. Conventionally, an ID code is disposed on a specific location of the substrate strip outside the substrate units for further production management, quality control, and failure tracking during substrate fabricating processes. However, the ID codes will be removed or covered after the semiconductor packaging processes. Moreover, the substrate cost is increased by putting substrate ID codes on the substrate strip.
According to a conventional method for forming substrate ID codes in semiconductor packages, the ID codes are formed in one thin metal film or other metal layers of the circuit substrate by a metal etching. However; the ID codes are covered by packaging components such as a chip or an encapsulant during semiconductor packaging processes and can not be recognized by vision inspections. Therefore, the ID codes of the substrates can not provide any information for quality control or failure tracking and management or process improvement from semiconductor packages.